Reagent for the determination of lipase and process for preparing same

Abstract

A reconstitutable dry reagent for the turbidimetric determination of lipase, which reagent forms an emulsion upon adding water and comprises substrate oil, protective colloid, emulsifier and activator; and the process for making said dry reagent comprising preparing an aqueous emulsion of a triglyceride containing bile acid salt, colipase, at least 10% by weight of protective colloid, and at least a part of a preserving agent, lyophilizing the emulsion, mixing the lyophilizate with a buffer substance and urea, and recovering said dry reagent.

We claim: 
     
       1. A reconstitutable dry reagent for the turbidimetric determination of lipase, which reagent forms an emulsion upon adding water and comprises substrate oil, protective colloid, emulsifier and an activator for lipase, said reagent containing: 0.2 to 10% by weight of liquid triglyceride,   20 to 90% by weight of protective colloid,   5 to 60% by weight of an alkali metal salt of bile acid,   0.001 to 0.1% by weight of colipase,   0.1 to 2.0% by weight of preserving agent,   5 to 20% by weight of urea,   3 to 50% by weight of buffer substance for pH 6.0 to 10.5 and   0.5 to 5% by weight of said activator.   
     
     
       2. A reagent as claimed in claim 1 wherein the fatty acid residues of the triglyceride each contain 8 to 20 carbon atoms and 1 to 8 carbon-carbon double bonds. 
     
     
       3. A reagent as claimed in claim 1 containing 0.2 to 2.0% by weight of triglyceride. 
     
     
       4. A reagent as claimed in claim 1 wherein the protective colloid is one or more polyhydroxy compounds. 
     
     
       5. A reagent as claimed in claim 4 wherein the polyhydroxy compound is a monomeric or polymeric pentose or hexose containing up to 10 pentose to hexose units in the molecule. 
     
     
       6. A reagent as claimed in claim 5 wherein the polyhydroxy compound is a solid polyethylene glycol. 
     
     
       7. A reagent as claimed in claim 1 containing 50 to 70% by weight of protective colloid. 
     
     
       8. A reagent as claimed in claim 1 containing 10 to 15% by weight of bile acid salt. 
     
     
       9. A reagent as claimed in claim 1 containing 0.003 to 0.01% by weight of colipase. 
     
     
       10. A reagent as claimed in claim 1 wherein the preserving agent is an alkali metal azide. 
     
     
       11. A reagent as claimed in claim 1 containing 10 to 15% by weight of urea. 
     
     
       12. A reagent as claimed in claim 1 containing 3 to 10% by weight of buffer substance. 
     
     
       13. A reagent as claimed in claim 1 wherein the buffer substance is hepes buffer, tabs buffer, Good buffer, tris buffer, triethanolamine buffer or diethanolamine buffer. 
     
     
       14. A reagent as claimed in claim 1 wherein the activator is sodium, calcium or magnesium chloride. 
     
     
       15. Process for the preparation of a dry reagent as claimed in claim 1 which process comprises preparing an aqueous emulsion of a triglyceride containing bile acid salt, colipase, at least 10% by weight of protective colloid, and at least a part of a preserving agent, lyophilizing the emulsion, mixing the lyophilizate with a buffer substance and urea and recovering said dry reagent. 
     
     
       16. Process as claimed in claim 15 wherein said aqueous emulsion also contains an activator. 
     
     
       17. Process as claimed in claim 15 wherein the said lyophilizate is mixed with a buffer and urea and additionally at least one of a protective colloid, a preserving agent and an activator. 
     
     
       18. Process as claimed in claim 15 wherein, into a solution of protective colloid, bile acid salt, colipase and optionally preserving agent and activator, there is injected in a fine stream, while stirring, a solution of the triglyceride in a volatile organic solvent.